IAM JSON Policy Elements: Effect

The Effect element is required and specifies whether the statement results in
an allow or an explicit deny. Valid values for Effect are Allow and
Deny.

"Effect":"Allow"

By default, access to resources is denied. To allow access to a resource, you must
set the
Effect element to Allow. To override an allow (for example, to
override an allow that is otherwise in force), you set the Effect element to
Deny. For more information, see IAM JSON Policy Evaluation Logic.